1. Inorganic Crystal Structure Database, Fachinformationszentrum Energie Physik Mathematik Karlsruhe, Federal Republic of Germany.
2. Metal Data File, National Research Council of Canada, Ottawa, Canada.
3. Crystal Data File, National Institute of Standards and Technology, Washington, U.S.A.
4. Powder Diffraction File, International Center for Powder Diffraction Data, Swarthmore, U.S.A.
5. Cambridge Crystallographic Database, Crystallographic Data Centre, University Chemical Laboratory, Cambridge, Great Britain.